Dr Uri Bakay:
The term is used once in shas in Chulin 90b albeit in a different way then what it means now. Although it is a recent innovation, it definitely preceded R’ Moshe – you can begin seeing its usage circa the beginning of the 1900s in certain Rabbinical writings (e.g. R’ Elchanan Wasserman) and Agudas Yisrael along with the Jewish Observer brought it to the masses.